This invention relates to semiconductor processing methods of forming a contact opening.
Semiconductor fabrication typically involves forming conductive connections between substrate locations which are elevationally separated by one or more layers. To do so, portions of such layers must ordinarily be removed. Typically, such layer portions are removed by patterning and etching a contact opening through the overlying layers of material to expose an elevationally lower substrate location with which a conductive connection is desired. Such constitutes a first masking step in which a first mask is used to pattern the desired contact opening.
Subsequently, conductive material is formed within the contact opening to interconnect desired elevationally separated layers. Typically, following the interconnect step, the outermost elevationaly. separated layer is patterned and etched in a second masking step which. utilizes a second mask which is different from the first mask. Such might be the case when, for example, the outermost layer is patterned into a conductive line.
Accordingly, at least two separate masks are needed to respectively pattern two different layers of photoresist which are required to be formed at separate times over the substrate and at different processing points in the processing flow. It is desirable to reduce the number of processing steps which are required in a processing flow.
This invention grew out of concerns associated with simplifying semiconductor processing and reducing the number of processing steps which are required in a processing flow.
The invention provides methods of forming contact openings over a substrate to a substrate location with which electrical connection is desired. According to one aspect, a multi-level layer. comprising masking material is formed atop an electrically conductive substrate surface and defines a mask opening through which a,contact opening is to be formed to an elevationally lower substrate location. The masking material constitutes a single layer of photoresist which is patterned to form an elevationally thicker first layer immediately laterally adjacent the mask opening than a second layer which is formed laterally outward of the first layer. The electrically conductive substrate surface is etched through the mask opening to form the contact opening over the substrate location. The masking material second layer is then removed and the conductive substrate surface is etched to form at least a portion of an outer conductive component. Thereafter, conductive material is formed in the contact opening to electrically connect elevationally separated layers.
According to another aspect, a masking material layer is formed over a substrate outer surface and defines a pattern for a contact opening which is to be etched through the outer surface. In a preferred implementation, the masking material layer comprises a bi-level profile having two different layer elevational thicknesses, the greater of which being disposed immediately laterally adjacent the contact opening pattern. A contact opening is subsequently etched through the substrate outer surface to a substrate location. Conductive material is formed within the contact opening to electrically connect the substrate location with an outer layer.
In a preferred implementation, the masking material layer is photoresist formed through photolithography using only a single mask. In another implementation, more than one mask is used to define the multi-level or bi-level profile masking material layer. The multi-level masking layer can have more than two levels.